Giant Lightning Eel

The eel can breathe only underwater.

The eel makes two bite attacks.

Melee Weapon Attack: +5 to hit, reach 5 ft., one target. Hit: 10 (2d6 + 3) piercing damage plus 4 (1d8) lightning damage.

One creature the eel touches within 5 feet of it outside water, or each creature within 15 feet of it in a body of water, must make a DC 12 Constitution saving throw. On failed save, a target takes 13 (3d8) lightning damage. If the target takes any of this damage, the target is stunned until the end of the eel's next turn. On a successful save, a target takes half as much damage and isn't stunned.